When word first leaked in early 2004 that Green Day was recording a rock- opera concept album, critics were leery and curious.

Sure, Green Day was one of the bigger bands of the previous decade, but the group’s last outing at the time was “Warning,” an abject pop-punk failure.

No big single. No relevance. It was a low point for the band.

And then “American Idiot” came out, spinning off big singles and bleeding political relevance. Pop-punk conquered the rock opera, and the record relaunched Green Day’s career into the rock stratosphere.

Funny. Right around that time, New Jersey’s My Chemical Romance, which plays Magness Arena on Sunday, was hitting the charts with its accomplished major label debut, “Three Cheers For Sweet Revenge.” Through that success, MCR scored an opening slot on a Green Day tour. And you have to wonder if they monitored Green Day’s game plan: When MCR returned to the recording studio, they were determined to make an important concept record.

A concept album

“We knew that we were going to tell a story,” MCR guitarist Frank Iero said recently from Los Angeles. “With our first record, we wrote concept songs but not a concept record. We really ran with ‘Demolition Lovers’ (from first record ‘I Brought You My Bullets You Brought Me Your Love’) and continued that to ‘Three Cheers,’ which was loosely based not on a concept but a thought-out story.

“This record is tighter,” he said. “It’s tight in keeping with themes and characters that were set forth with the story. We wanted to take the listener on a journey by writing songs that take on different landscapes musically.”

Concept records are tough. Sometimes they are the capstone in an artist’s catalog, tapping into storytelling, character development, theatricality and exposition. In other cases they’re awkward missteps, shallow attempts at something deep.

While “The Black Parade” is not The Who’s “Tommy” – or “American Idiot,” for that matter – it’s still a bold pop statement from a young band. In a short time, My Chemical Romance has wooed the kids with its aggressive pop-punk. Its previous outings were typically overwrought – pop emo, yes – and a tad vapid.

Some of that inexperienced songwriting plagues “The Black Parade,” which was released on Halloween 2006. Still, it’s a big step forward for MCR, a band that formed in the wake of 9/11, set on creating something meaningful.

The lead single “Welcome to the Black Parade,” begins with the simplicity of a piano and voice: “When I was a young boy, my father took me into the city to see a marching band. He said, ‘Son, when you grow up would you be the savior of the broken, the beaten and the damned?” It builds into a feast of horns and drums and stadium-styled guitars, and it’s not long before singer Gerard Way dons his best Freddie Mercury face. But it’s as if the late Queen singer were playing Jean Valjean, the protagonist in “Les Miserables.”

“Welcome to the Black Parade” isn’t as bombastic or original as “Bohemian Rhapsody” or “Les Mis,” but it’s undoubtedly a fun experiment – and pretty gutsy for such a popular, youth-skewing band. The rest of the record is full of solid, if overproduced, ruminations on life, love and death.

“I’m a fan of records you get and you listen to them from beginning to finish – records where everything is there for a purpose,” said Iero. “There was never any filler on those records – it was all well planned out. And you had to look into it deeply, because the artwork meant something, the lyrics and pictures and art were all tied together, and if you loved the band, you loved the songs.

“Maybe it’s the computer age or lack of work ethic or craftsmanship, but a lot of artists are now like, ‘Here are a few singles, and here’s some filler, and it doesn’t matter.’ But for us, every aspect of the band and our music matters – from the website, (merchandise) and artwork to everything else. It’s about time that rock with a purpose came back.”

Taking it live

That might be overstating his case, but it will be interesting to see how the band plays the record live. Touring a successful concept record can make for the ultimate triumph, especially when artists are willing to be as arty and risky on stage as they were in the studio. The Who’s big “Tommy” tours, featuring the opus played in its entirety, are the stuff of legend.

But while MCR has plans for plenty of visual spectacle, they have yet to act on the riskier ideas.

“We’ve also thought about, in doing the whole record, playing the songs in a different order and changing the meaning,” Ieror said. “It’s the great thing about this record we made. When the order of the songs are changed, there’s a completely different outcome.

“We might go in and mold the story differently, maybe leaving some songs out of the mix. Maybe the listener will walk away with a different feeling about the record than the one they walked in with.”

Ricardo Baca is the editor of The Cannabist. After 12 years as The Denver Post's music critic and a couple more as the paper's entertainment editor, he was tapped to become The Post's first ever marijuana editor and create The Cannabist in late-2013. Baca also founded music blog Reverb and co-founded music festival The UMS.